This invention is generally in the field of ophthalmic therapies, and more particularly to the use of a microneedle for infusion of a fluid drug formulation into ocular tissues for targeted, local drug delivery.
The delivery of drug to the eye is extremely difficult, particularly delivery of macromolecules and delivery to the back of the eye. Many inflammatory and proliferative diseases in the posterior region of the eye require long term pharmacological treatment. Examples of such diseases include macular degeneration, diabetic retinopathy, and uveitis. It is difficult to deliver effective doses of drug to the back of the eye using conventional delivery methods such as topical application, which has poor efficacy, and systemic administration, which often causes significant side effects. (Geroski & Edelhauser, Invest. Ophthalmol. Vis. Sci. 41:961-64 (2000)). For example, while eye drops are useful in treating conditions affecting the exterior surface of the eye or tissues at the front of the eye, the eye drops cannot significantly penetrate to the back of the eye, as may be required for the treatment of various retinal diseases.
Direct injection into the eye, using conventional needles and syringes is often effective, but requires professional training and raises concerns about safety (Maurice, J. Ocul. Pharmacol. Ther. 17:393-401 (2001)). It also would be desirable to be able to minimize the number and/or frequency of eye injection treatments needed to deliver therapeutically effective amounts of drug to the ocular tissue sites that need it.
The suprachoroidal space of the eye has been studied, and its cannulation described as a possible route for drug delivery. See, e.g., Olsen, et al., American J. Ophthalmology 142(5): 777-87 (November 2006); PCT Patent Application Publication No. WO 2007/100745 to Iscience Interventional Corporation.
It therefore would be desirable to provide better, safer, more effective techniques for the direct delivery of therapeutic agents to eye tissues. It also would be desirable to provide devices useful in such techniques which can be relatively inexpensive to produce and use. It further would be desirable to provide methods for pinpoint delivery of drug to sclera, choroidal, uveal, macular, ciliary, vitreous and retinal tissues.